A proposal to build a 38,000-square-foot shopping center on the site of the former Rolle Brothers property on Route 58 was given a two-year extension Thursday night for a series of previously approved Zoning Board of Appeals variances that were about to expire.

While three major construction projects on Route 58 within a quarter-mile have hummed along over the past couple of months, farther east up the road, progress at the Northville Commerce Park is moving along as well.

And new tenants are expected by the spring.

Sited at the corner of Northville Turnpike and Route 58, businesses at the planned 28,000-square-foot office complex are expected to start moving in come May, said Richmond Realty realtor Ike Israel, the property’s co-developer.

Work on the complex, which Mr. Israel said will ultimately contain four 7,200-square-foot buildings, began earlier this year.

The structural steel for one building has been erected and the foundation for another building is in the ground, Mr. Israel said. The exterior shell of a third building has also been constructed.

The building’s uses are still being determined, Mr. Israel said, but they will likely house medical and professional offices.

“We are negotiating with various types of tenants,” he said, adding that there are still some available spaces in the complex.

Mr. Israel’s vision for the complex, he said, is “Office space that has high exposure and is convenient to the hospital and the rest of Riverhead.”

Mr. Israel, who is developing the industrial park with his father – Richmond Realty broker and owner Richard Israel – said he hopes the complex will be completely finished by fall 2014.

“Our speed of construction is weather-dependent,” Ike Israel said.

Work on the project first began in 2010, when Riverhead-based Richmond Realty entered into a contract for the property. They began submitting site plans for approval in 2011.

Just east of the Riverhead Raceway sits another recently-completed shopping center, which contains a just-opened Dick’s Sporting Goods and Five Below. Starbucks, Buffalo Wild Wings and Christmas Tree Shops — all located in the plaza — are slated to open in the next few months.